FIG. 1 is a perspective view to show a body of an automobile. The body of an automobile includes various structural members. For example, when an automobile is subjected to a side collision, an injury value of an occupant largely depends on deformation behaviors of a center pillar 1, a side sill 2, and a roof rail 3 among the structural members. The center pillar 1 is disposed in an upright orientation at each of both sides of the body. The side sill 2 is connected to a lower end of the center pillar 1. The roof rail 3 is connected to an upper end of the center pillar 1. The side sill 2 and the roof rail 3 extend in the fore-and-aft direction of the body.
In the development of an automobile, it is essential to evaluate the performance of structural members against side collision. In general, automobile manufacturers fabricate a proto-type vehicle and performs a side collision test by using the proto-type vehicle (hereafter, also referred to as a “real-vehicle test”) to evaluate the performance of the structural members. However, such a proto-type vehicle is costly, and the fabrication time of the proto-type vehicle is long. For that reason, chances of performing such evaluation by a real-vehicle test are limited. Moreover, when a problem occurs in the performance of a structural member in a real-vehicle test, it becomes necessary to fabricate another proto-type vehicle of a modified design and perform the real-vehicle test again, causing the automobile development to be delayed. Particularly, since the period of automobile development has been shortened in recent years, it is difficult to perform real-vehicle tests at many conditions. Therefore, it is also not easy to adopt a new material, a new structure, and like for the structural members.
Further, it is difficult for material manufacturers (for example, steel manufacturers), parts manufacturers, and the like other than automobile manufacturers to perform a real-vehicle test independently. This is because there are constraints in the preparation of proto-type vehicles, the construction of real-vehicle test facilities, and the like. For that reason, it is very difficult for a manufacturer of starting material, a manufacturer of parts, or the like to evaluate the collision performance of its own product.
Therefore, it is particularly desirable to perform a collision test by using a single structural member without performing a real-vehicle test which uses a proto-type vehicle, as a technique for evaluating the performance of a structural member against side collision.
For example, Japanese Patent Publication No. 4902027 (Patent Literature 1) discloses a technique of selecting a structural member which has a large contribution to absorption of collision energy, and evaluating the collision performance of this single structural member. It is described that the technique of Patent Literature 1 makes it possible to accurately evaluate performance by performing a collision test using, as a test sample, a center pillar or the like, which undergoes bending deformation during a side collision without fabricating a proto-type vehicle.
FIG. 2 is a side view to show a collision test apparatus disclosed in Patent Literature 1. As shown in FIG. 2, in a collision test of Patent Literature 1, a center pillar assembly 5 among structural members is used as the test sample. The center pillar assembly 5 includes a pillar part 5a, a lower horizontal part 5b which extends from a lower end of the pillar part 5a in a fore-and-aft direction, and an upper horizontal part 5c which extends from an upper end of the pillar part 5a in the fore-and-aft direction. The center pillar assembly 5 is supported at a total of four portions including the front end and rear end of the lower horizontal part 5b and the front end and rear end of the upper horizontal part 5c via a flywheel 104, respectively. During the collision test, an impact is applied to the pillar part 5a by an impactor 17 which moves in the horizontal direction. The flywheel 104 serves to simulate deformation resistance of the side sill 2 and the roof rail 3 when subjected to an impact load, and reproduces deformation behavior of the center pillar 1 similar to that in a real-vehicle test.
In reality, however, upon a side collision in a real-vehicle test, the side sill 2 and the roof rail 3 undergo torsional deformation and bending deformation at the same time as the pillar part 5a undergoes bending deformation. In other words, the side sill 2 and the roof rail 3 undergo plastic deformation. In this respect, in the technique of Patent Literature 1, the flywheel 104 which simulates the side sill 2 and the roof rail 3 allows rotation and does not undergo plastic deformation. For that reason, there is a risk that results obtained from the collision test of Patent Literature 1 deviate from results of a real-vehicle test.
Moreover, the technique of Patent Literature 1 is laborious in assembling the center pillar assembly 5 to the test apparatus. Further, during a collision test of Patent Literature 1, the deformation behavior of the pillar part 5a is observed by a camera (not shown). In that occasion, the flywheel 104 hinders the photographing by the camera.